Recently, a sensor-equipped display device comprising a sensor (also called a touchpanel) which detects a touch or approach of an object is used. A capacitive sensor which detects a touch or approach of a conductor such as a finger based on variations in capacitance is an example of the sensor. Detection electrodes and sensor drive electrodes constituting such a sensor are provided in a display area in which an image is displayed and are opposed to each other through a dielectric.